Multiunit electron tube



April 1949- w. w. EITEL ET AL 2,468,434

MULTIUNIT ELECTRON TUBE Filed June 9, 1947 5 Sheets-Sheet l INVENTORS MLL/AM M E/TEL.

BY dAc AM CULL UGH JLMZ ATTOR NE Y April 26, 1949. w. w. ElTEL ET AL MULTIUNIT ELECTRON TUBE 5 Sheets-Sheet 2 Filed June 9, 1947 INVENTORS W/LL./AM W. E1751;

ATTORNEY April 1949- w. w. ElTEL ET AL 2,468,434

MULTIUNIT ELECTRON TUBE Filed June 9, 1947 5 Sheets-Sheet 5 ILL g. 5

INVENTORS WILL/AM MK E/TEL By JACK A. M9 CULL'OUGH JM 6. 22V

ATTORNE Y Patented Apr. 26, 1949 UNITED STATES PATENT OFFICE.

MULTIUNIT ELECTRON TUBE tion of California Application June 9, 1947, Serial No. 753,495

8 Claims.

sired electrical properties for good operation at 7 high frequencies with tubes of small physical size because small tubes have certain inherent advantages from the standpoint of tube structure and geometry, such as maintaining closer electrode spacings and lower inductance leads. The disadvantage of small structures for power tube uses is the limitation on power output due to lack of heat dissipation from the electrodes, particularly from the anode. In other words, large physical size is incompatible with electrical properties required for higher frequency opera tion, and this would appear to put a ceiling on power output for high frequency tubes.

The broad object of our invention is to provide a tube capable of large power output without sacrifice of those electrical properties required for high frequency operation.

Another important object is to provide a tube structure whi h simplifies the manufacture of po er tubes, and which enables a variety of tube of difierent power ratings to be built, all from basic tubes units made alike.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of our invention. It is to be understood that we do not limit ourselves to this disclosure of species of our invention, as we may adopt variant embodiments thereoi within the scope of the claims.

Referring to the drawings:

Figure 1 is a plan view showing a multi-unit tube embodying the improvements of our invention; and

Figure 2 is a detailed sectional View taken axially of one of the tube units.

Figure 3 is a View similar to Figure 1 showing a modified arrangement.

In terms of broad inclusion, our electron tube comprises a plurality of radially disposed tube units rigidly connected together as a single structural body, each unit having an individual envelope and a plurality of electrodes, and a circular terminal member common to corresponding electrodes of the tube units. Each tube unit preferably has an external anode formed as a portion of the envelope, and a cooler structure is provided connecting the anodes. In one form of construction the anodes project inwardly and are embraced by a central cooler structure, and in another form the anodes project outwardly and are embraced by a ring-shaped cooler structure.

In greater detail, Figures 1 and 2 show a construction in which the anodes project inwardly. We show six triode units 2, it being understood that a greater or less number of units may be employed and that the individual units may be other than triodes such as diodes or tetrodes, the total power output increasing with the number of units. The tube units each have an individual envelope, and those illustrated each have a plurality of electrodes including an anode 3, filamentary cathode 4 and control grid 6, these being complete tubes independently constructed and evacuated.

Anodes 3 are preferably of the external anode type adapted for cooling by forced air or the like. The anodes constitute the end portions of the envelopes and are embraced by and connected to a common central cooler structure 1. This cooler structure is circular in shape with an axis coincident with the axis toward which the tube units radiate. In addition to cooling the anodes the cooler structure also functions as an electrical terminal for the anodes as Well as a supporting connection for tying the tube units together.

The cooler structure in Figure 1 is circular or ring-shaped made up of a series of concentric fins 8, say of copper or aluminum, secured to tubular cores 9 for receiving the anodes 3, the latter being secured to the cores by solder H. Cooling air may be directed either upwardly or downwardly towards the cooler.

In the tube units illustrated anode 3 is a metal cup carrying an exhaust tubulation l3 and a sealing flange [5. Metallic tubulation I 3 is pinched off at tip I4 after evacuation of the envelope. Flange I5 is sealed to a cylindrical envelope section iii of vitreous material such as glass. A grid connector ring [1 interposed in the envelope wall is sealed to section It, and a pair of concentric cathode connector members it and 59 are arranged coaxially with grid ring il at the envelope end opposite the anode. The envelope is completed by a glass section 2| sealed between the grid ring and tubular outer cathode connector l8, and by a glass ring 22 sealed between metal flanges 23 and 24 on the cathode connector members.

Internally of the envelope the cage type control grid 6 is supported on its connector ring I! by a conical bracket 26. The filamentary cathode illustrated is made of hairpins of thoriated tungsten wire secured to alternate tabs on flared supports 2'! and 28 connected to tubular extenslons 29 and 3| on the cathode connector members l8 and 59. These filaments are tensioned by a spring pressed sleeve 32 sliding on center rod 33 and bearing against an upper spider 36 having radial arms engaging the bights of the filaments. This particular filament structure forms no part of the present invention, it being understood that any suitable cathode, either filamentary or of the indirectly heated type, may be used. It is also understood that the structure of the tube unit may be varied widely in other respects, since the inventive idea relates to joining together radially disposed units into a single structural body rather than to the detailed construction of the individual units.

Externally of the tube units the grids are connected together by a common circular terminal 36 which is preferably a rigid ring-shaped metal member coaxial with the cooler structure and having apertures receiving the grid rings l1. The terminal member may be fastened to the grid rings in any suitable manner such as by Soldering or by use of a mechanical clamping device. A pair of cathode terminal rings 31 and 38 coaxial with and spaced outwardly from grid terminal 36 are likewise provided with apertures for receiving the respective cathode members l8 and I9. It will be seen that the metallic terminal members 36, 3'! and 33 function to mechanically tie the outer portions of the tube units together as well as to provide electrical connections between corresponding electrodes. The units are thus rigidly connected at the inner ends by the cooler structure and at the outer ends by the terminal rings.

Our improved multi-unit tube in which the tube units are radially disposed provides a coaxial terminal arrangement which is particularly well adapted for use in coaxial line high frequency circuits, it being understood that the tubular lines of the anode, grid and cathode circuits may be extended axially of the composite tube and in either or both directions from the tube.

In the modified structure shown in Figure 3 the units 2 are arranged with anodes 3 projecting outwardly so that the anodes radiate toward an outer ring-shaped cooler structure 39 having fins 8 similar to those shown in Figure 1. The grid terminal member M and cathode terminal members 42 and 53 in this case lie inside the cooler structure. These circular or ring-shaped terminal members may be either true circles as shown by the cathode terminals 42 and $3 or flat sided as illustrated by the grid terminal 4|. This reversal of the terminal arrangement compared to Figure 1 is desirable in some kinds of circuits.

While We have shOWn cooler structures adapted for cooling by forced air, it is understood that the structures may be annular water jackets for cooling by water circulation.

We claim;

1. A multi-unit electron tube comprising a plurality of tube units rigidly connected together as a single structural body, said units being disposed with their longitudinal axes extending radially from a central axis, each unit having an individual envelope and a plurality of electrodes, and a circular terminal common to correspondin electrodes of said tube units.

2. A multi-unit electron tube comprising a plurality of tube units rigidly connected together as a single structural body, said units being disposed with their longitudinal axes extending radially from a central axis, each unit having an individual envelope and a plurality of electrodes including a grid and cathode, a ring-shaped terminal common to the grids of said units, and another ring-shaped terminal common to the cathodes of said units.

3. A multi-unit electron tube comprising a plurality of tube units rigidly connected together as a single structural body, said units being disposed with their longitudinal axes extending radially from a central axis, each unit having an individual envelope and a plurality of electrodes, and a rigid circular member tying the tube units together, said member affording a supporting connection between the tube units and providing an electrical connection between corresponding electrodes of said tube units.

4. A multi-unit electron tube comprising a plurality of tube units connected together as a single structural body, each unit comprising an individual envelope having an inner end portion forming an external anode, and a central cooler structure from which the units radiate connecting the anodes of said units.

5. A multi-unit electron tube comprising a plurality of tube units connected together as a single structural body, each unit comprising an individual envelope having an outer end portion forming an external anode, and a ring-shaped cooler structure toward which the units radiate connecting the anodes of said units.

6. A multi-unit electron tube comprising a plurality of tube units rigidly connected together as a single structural body, said units being disposed with their longitudinal axes extending radially from a central axis, each unit having an individual envelope and a plurality of electrodes, a portion of the envelope constituting an external anode, a circular cooler structure embracing the anodes and providing a direct electrical connection between said anodes, a circular terminal member coaxial with the cooler structure and providing a direct electrical connection between corresponding electrodes of said tube units, said cooler structure and terminal member affording supporting connections between the tube units.

7. A multi-unit electron tube comprising a plurality of tube units rigidly connected together as a single structural body, said units being disposed with their longitudinal axes extending radially from a central axis, each unit having an individual envelope and a plurality of electrodes, the inner end portion of the envelope constituting an external anode, a central cooler structure from which the units radiate embracing the anodes and providing a direct electrical connection between said anodes, and a ring-shaped terminal member spaced outwardly of the cooler structure and providing a direct electrical connection between corresponding electrodes of said tube units, said cooler structure and terminal member affording supporting connections between the tube units.

8. A multi-unit electron tube comprising a plurality of tube units rigidly connected together as a single structural body, said units being disposed with their longitudinal axes extending radially from a central axis, each unit having an individual envelope and a plurality of electrodes, the outer end portion of the envelope constituting an external anode, a ring-shaped cooler structure toward which the units radiate embracing the anodes and providing a direct electrical connec- REFERENCES CITED tion between said anodes, and a circular terminal The following references are of record in the member spaced inwardly of the cooler structure file of this patent: and providing a direct electrical connection be- 5 tween corresponding electrodes of said tube units, UNITED STATES PATENTS said cooler structure and terminal member af- Nu ber Name Date fording supporting connections between the tube 2,424,533 Eitel 815 July 1 7 units. 2,424,685 Eitel et a1. July 29, 1947 WILLIAM W. EITEL. l0

JACK A. MCCUILOUGH. 

